/**
 * A mixin to add floating capability to a Component.
 */
Ext.define('Ext.util.Floating', {

    uses: ['Ext.Layer', 'Ext.window.Window'],

    /**
     * @cfg {Boolean} focusOnToFront
     * Specifies whether the floated component should be automatically {@link Ext.Component#method-focus focused} when
     * it is {@link #toFront brought to the front}.
     */
    focusOnToFront: true,

    /**
     * @cfg {String/Boolean} shadow
     * Specifies whether the floating component should be given a shadow. Set to true to automatically create an
     * {@link Ext.Shadow}, or a string indicating the shadow's display {@link Ext.Shadow#mode}. Set to false to
     * disable the shadow.
     */
    shadow: 'sides',

    /**
     * @cfg {String/Boolean} shadowOffset
     * Number of pixels to offset the shadow.
     */

    constructor: function (dom) {
        var me = this;

        me.el = new Ext.Layer(Ext.apply({
            hideMode     : me.hideMode,
            hidden       : me.hidden,
            shadow       : (typeof me.shadow != 'undefined') ? me.shadow : 'sides',
            shadowOffset : me.shadowOffset,
            constrain    : false,
            shim         : (me.shim === false) ? false : undefined
        }, me.floating), dom);

        // release config object (if it was one)
        me.floating = true;
        
        // Register with the configured ownerCt.
        // With this we acquire a floatParent for relative positioning, and a zIndexParent which is an
        // ancestor floater which provides zIndex management.
        me.registerWithOwnerCt();
    },

    registerWithOwnerCt: function() {
        var me = this;

        if (me.zIndexParent) {
            me.zIndexParent.unregisterFloatingItem(me);
        }

        // Acquire a zIndexParent by traversing the ownerCt axis for the nearest floating ancestor
        me.zIndexParent = me.up('[floating]');
        me.setFloatParent(me.ownerCt);
        delete me.ownerCt;

        if (me.zIndexParent) {
            me.zIndexParent.registerFloatingItem(me);
        } else {
            Ext.WindowManager.register(me);
        }
    },

    setFloatParent: function(floatParent) {
        var me = this;

        // Remove listeners from previous floatParent
        if (me.floatParent) {
            me.mun(me.floatParent, {
                hide: me.onFloatParentHide,
                show: me.onFloatParentShow,
                scope: me
            });
        }

        me.floatParent = floatParent;

        // Floating Components as children of Containers must hide when their parent hides.
        if (floatParent) {
            me.mon(me.floatParent, {
                hide: me.onFloatParentHide,
                show: me.onFloatParentShow,
                scope: me
            });
        }

        // If a floating Component is configured to be constrained, but has no configured
        // constrainTo setting, set its constrainTo to be it's ownerCt before rendering.
        if ((me.constrain || me.constrainHeader) && !me.constrainTo) {
            me.constrainTo = floatParent ? floatParent.getTargetEl() : me.container;
        }
    },
    
    onAfterFloatLayout: function(){
        this.syncShadow();   
    },

    onFloatParentHide: function() {
        var me = this;

        if (me.hideOnParentHide !== false && me.isVisible()) {
            me.hide();
            me.showOnParentShow = true;
        }
    },

    onFloatParentShow: function() {
        if (this.showOnParentShow) {
            delete this.showOnParentShow;
            this.show();
        }
    },

    // private
    // z-index is managed by the zIndexManager and may be overwritten at any time.
    // Returns the next z-index to be used.
    // If this is a Container, then it will have rebased any managed floating Components,
    // and so the next available z-index will be approximately 10000 above that.
    setZIndex: function(index) {
        var me = this;

        me.el.setZIndex(index);

        // Next item goes 10 above;
        index += 10;

        // When a Container with floating descendants has its z-index set, it rebases any floating descendants it is managing.
        // The returned value is a round number approximately 10000 above the last z-index used.
        if (me.floatingDescendants) {
            index = Math.floor(me.floatingDescendants.setBase(index) / 100) * 100 + 10000;
        }
        return index;
    },

    /**
     * Moves this floating Component into a constrain region.
     *
     * By default, this Component is constrained to be within the container it was added to, or the element it was
     * rendered to.
     *
     * An alternative constraint may be passed.
     * @param {String/HTMLElement/Ext.Element/Ext.util.Region} [constrainTo] The Element or {@link Ext.util.Region Region}
     * into which this Component is to be constrained. Defaults to the element into which this floating Component
     * was rendered.
     */
    doConstrain: function(constrainTo) {
        var me = this,

            // Calculate the constrain vector to coerce our position to within our
            // constrainTo setting. getConstrainVector will provide a default constraint
            // region if there is no explicit constrainTo, *and* there is no floatParent owner Component.
            vector = me.getConstrainVector(constrainTo),
            xy;

        if (vector) {
            xy = me.getPosition(!!me.floatParent);
            xy[0] += vector[0];
            xy[1] += vector[1];
            me.setPosition(xy);
        }
    },


    /**
     * Gets the x/y offsets to constrain this float
     * @private
     * @param {String/HTMLElement/Ext.Element/Ext.util.Region} [constrainTo] The Element or {@link Ext.util.Region Region}
     * into which this Component is to be constrained.
     * @return {Number[]} The x/y constraints
     */
    getConstrainVector: function(constrainTo){
        var me = this;

        if (me.constrain || me.constrainHeader) {
            constrainTo = constrainTo || (me.floatParent && me.floatParent.getTargetEl()) || me.container || me.el.getScopeParent();
            return (me.constrainHeader ? me.header.el : me.el).getConstrainVector(constrainTo);
        }
    },

    /**
     * Aligns this floating Component to the specified element
     *
     * @param {Ext.Component/Ext.Element/HTMLElement/String} element
     * The element or {@link Ext.Component} to align to. If passing a component, it must be a
     * component instance. If a string id is passed, it will be used as an element id.
     * @param {String} [position="tl-bl?"] The position to align to
     * (see {@link Ext.Element#alignTo} for more details).
     * @param {Number[]} [offsets] Offset the positioning by [x, y]
     * @return {Ext.Component} this
     */
    alignTo: function(element, position, offsets) {

        // element may be a Component, so first attempt to use its el to align to.
        // When aligning to an Element's X,Y position, we must use setPagePosition which disregards any floatParent
        this.setPagePosition(this.el.getAlignToXY(element.el || element, position, offsets));
        return this;
    },

    /**
     * Brings this floating Component to the front of any other visible, floating Components managed by the same
     * {@link Ext.ZIndexManager ZIndexManager}
     *
     * If this Component is modal, inserts the modal mask just below this Component in the z-index stack.
     *
     * @param {Boolean} [preventFocus=false] Specify `true` to prevent the Component from being focused.
     * @return {Ext.Component} this
     */
    toFront: function(preventFocus) {
        var me = this;

        // Find the floating Component which provides the base for this Component's zIndexing.
        // That must move to front to then be able to rebase its zIndex stack and move this to the front
        if (me.zIndexParent && me.bringParentToFront !== false) {
            me.zIndexParent.toFront(true);
        }
        
        if (!Ext.isDefined(preventFocus)) {
            preventFocus = !me.focusOnToFront;
        }
        
        if (preventFocus) {
            me.preventFocusOnActivate = true;
        }
        if (me.zIndexManager.bringToFront(me)) {    
            if (!preventFocus) {
                // Kick off a delayed focus request.
                // If another floating Component is toFronted before the delay expires
                // this will not receive focus.
                me.focus(false, true);
            }
        }
        delete me.preventFocusOnActivate;
        return me;
    },

    /**
     * This method is called internally by {@link Ext.ZIndexManager} to signal that a floating Component has either been
     * moved to the top of its zIndex stack, or pushed from the top of its zIndex stack.
     *
     * If a _Window_ is superceded by another Window, deactivating it hides its shadow.
     *
     * This method also fires the {@link Ext.Component#activate activate} or
     * {@link Ext.Component#deactivate deactivate} event depending on which action occurred.
     *
     * @param {Boolean} [active=false] True to activate the Component, false to deactivate it.
     * @param {Ext.Component} [newActive] The newly active Component which is taking over topmost zIndex position.
     */
    setActive: function(active, newActive) {
        var me = this;
        
        if (active) {
            if (me.el.shadow && !me.maximized) {
                me.el.enableShadow(true);
            }
            if (me.modal && !me.preventFocusOnActivate) {
                me.focus(false, true);
            }
            me.fireEvent('activate', me);
        } else {
            // Only the *Windows* in a zIndex stack share a shadow. All other types of floaters
            // can keep their shadows all the time
            if (me.isWindow && (newActive && newActive.isWindow)) {
                me.el.disableShadow();
            }
            me.fireEvent('deactivate', me);
        }
    },

    /**
     * Sends this Component to the back of (lower z-index than) any other visible windows
     * @return {Ext.Component} this
     */
    toBack: function() {
        this.zIndexManager.sendToBack(this);
        return this;
    },

    /**
     * Center this Component in its container.
     * @return {Ext.Component} this
     */
    center: function() {
        var me = this,
            xy;
            
        if (me.isVisible()) {
            xy = me.el.getAlignToXY(me.container, 'c-c');
            me.setPagePosition(xy);
        } else {
            me.needsCenter = true;
        }
        return me;
    },
    
    onFloatShow: function() {
        if (this.needsCenter) {
            this.center();    
        }
        delete this.needsCenter;
    },

    // private
    syncShadow : function() {
        if (this.floating) {
            this.el.sync(true);
        }
    },

    // private
    fitContainer: function() {
        var me = this,
            parent = me.floatParent,
            container = parent ? parent.getTargetEl() : me.container;

        me.setSize(container.getViewSize(false));
        me.setPosition.apply(me, parent ? [0, 0] : container.getXY());
    }
});
